Fix git-format-patch usage string wrt output modes.
Fix git-format-patch usage string wrt output modes.

--stdout was not mentionned, and the description for the case where -o
was not given was thus incomplete.

Signed-off-by: Yann Dirson <69228ceb6f6706d8bbf6135fa4ad3d70b54c46ed@altern.org>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git